Oh, I've got another one!
How about this - if you have sex with your alternate genderbent self or form, would be considered incest?
...
...okay, what is wrong with me today?!
You know what, let's just forget the whole thing. It was my mistake - I certainly don't want to involve any discussions about masturbation or incest in a discussion as awesome as a genderbent SHnY.
And so...carry on, I guess...